/*
* Copyright 2016. the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.mongodb.core.aggregation;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import org.bson.Document;
import org.springframework.util.ObjectUtils;
/**
* @author Christoph Strobl
* @since 1.10
*/
abstract class AbstractAggregationExpression implements AggregationExpression {
private final Object value;
protected AbstractAggregationExpression(Object value) {
this.value = value;
}
/* (non-Javadoc)
* @see org.springframework.data.mongodb.core.aggregation.AggregationExpression#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
*/
@Override
public Document toDocument(AggregationOperationContext context) {
return toDocument(this.value, context);
}
@SuppressWarnings("unchecked")
public Document toDocument(Object value, AggregationOperationContext context) {
Object valueToUse;
if (value instanceof List) {
List<Object> arguments = (List<Object>) value;
List<Object> args = new ArrayList<Object>(arguments.size());
for (Object val : arguments) {
args.add(unpack(val, context));
}
valueToUse = args;
} else if (value instanceof java.util.Map) {
Document dbo = new Document();
for (java.util.Map.Entry<String, Object> entry : ((java.util.Map<String, Object>) value).entrySet()) {
dbo.put(entry.getKey(), unpack(entry.getValue(), context));
}
valueToUse = dbo;
} else {
valueToUse = unpack(value, context);
}
return new Document(getMongoMethod(), valueToUse);
}
protected static List<Field> asFields(String... fieldRefs) {
if (ObjectUtils.isEmpty(fieldRefs)) {
return Collections.emptyList();
}
return Fields.fields(fieldRefs).asList();
}
@SuppressWarnings("unchecked")
private Object unpack(Object value, AggregationOperationContext context) {
if (value instanceof AggregationExpression) {
return ((AggregationExpression) value).toDocument(context);
}
if (value instanceof Field) {
return context.getReference((Field) value).toString();
}
if (value instanceof List) {
List<Object> sourceList = (List<Object>) value;
List<Object> mappedList = new ArrayList<Object>(sourceList.size());
for (Object item : sourceList) {
mappedList.add(unpack(item, context));
}
return mappedList;
}
return value;
}
protected List<Object> append(Object value) {
if (this.value instanceof List) {
List<Object> clone = new ArrayList<Object>((List) this.value);
if (value instanceof List) {
for (Object val : (List) value) {
clone.add(val);
}
} else {
clone.add(value);
}
return clone;
}
return Arrays.asList(this.value, value);
}
@SuppressWarnings("unchecked")
protected java.util.Map<String, Object> append(String key, Object value) {
if (!(this.value instanceof java.util.Map)) {
throw new IllegalArgumentException("o_O");
}
java.util.Map<String, Object> clone = new LinkedHashMap<String, Object>((java.util.Map<String, Object>) this.value);
clone.put(key, value);
return clone;
}
protected List<Object> values() {
if (value instanceof List) {
return new ArrayList<Object>((List) value);
}
if (value instanceof java.util.Map) {
return new ArrayList<Object>(((java.util.Map) value).values());
}
return new ArrayList<Object>(Collections.singletonList(value));
}
protected abstract String getMongoMethod();
}